Sounding board construction for pianos



Patented Sept. 2 6, 19,39

UNITED STATES SOUNDING BOARD PIAN CONSTRUCTION FOR Francis C. Socin, St. Charles, Ill., assig'nor to The Rudolph Wurlitzer Company, Cincinnati, Ohio,

a corporation Application August 20,

5 Claims.

This invention relates to the construction of upright or vertical pianos, and particularly the present type of small upright piano generally measuring from 33 to 39% inches in height. The invention particularly relates to the arrangement and mounting of the sounding board.

In pianos of this type there is a shortage of sounding board area, thereby making the tone quality'less resonant and inferior to the tone quality of the larger pianos with the greater extent of sounding board area. The principal object of this invention is to substantially increase the sounding board area in any vertical piano of a given height, resulting in a more resonant and improved quality of tone. This is accomplished by extending the sounding board past the pin block, preferably spaced therefrom, to approximately the top of the piano casing, whereas heretofore it has been terminated along the lower edge of the block.

Another advantage of this construction resides in the spacing of the sounding board from the pin block at the top of the piano for providing a free passageway therebetween for the sound waves emanating from the full depth of the sounding board. Thus, instead of the sound being baied by the usual closed connection between the pin block and the sounding board along the upper edge thereof, such passageway permits a natural iiow of sound waves along the surface of the sounding board upwardly through the top of the piano, particularly when the top of the piano case is raised.

Thus, it will be understood from the following description and the attached drawing that the tone quality of the middle and bass sections of a piano of this construction are substantially improved, while free flow and unobstructed upward passage of the sound waves is permitted throughout their entire range.

Beyond certain limits it is known that increase of the sounding board is not desirable. Therefore, any part of the upper edge of the sounding board may be blocked or cut off between the sounding board and supporting back frame as is deemed advisable.

The full nature of the invention will be understood from the accompanying drawing and the following description and claims:

Fig. 1 is a sectional view through the back of an upright piano including the sounding board and string plate. Fig. 2 is the same as Fig. l, showing an enlargement of the upper portion thereof. Fig. 3 is a section .taken on the line 3-3 of Fig. 1.

1938, Serial No. 225,894

In the standard construction of upright pianos the sounding board extends from the extreme bottom of the casing to a position immediately beneath the pin block, the pin block being glued or secured directly to the back or skeleton frame. As shown herein, there is a piano back construction of the upright type having upright supports I0 with a top cross member II and a bottom cross member I2. Secured thereto there is a skeleton frame comprising end uprights I3, an upper cross member I4 and a lower cross member l5.

The sounding board I6 preferably extends throughout the entire area of the back portion of the piano, being secured at its ends to the end frame members i3 and at the top and bottom thereof to the cross members I4 and I5 so as to be held in spaced relation to the back of the casing and free from contact therewith so as to permit of vibration throughout its entire area. The sounding board I 6 is reinforced by the ribs or battens i? in the usual manner.

Forwardly of the sounding board there is provided the usual string plate I3 having a pin block I9 secured along the upper edge thereof and between the plate and sounding board. The tuning pins Z extend through openings in the string plate and are anchored in the pin block in the usual manner, to which the piano strings 2l are secured. The other ends of the strings, as in the usual practice, are secured to the hitch pins 22. The strings extend over a rib 23 formed on the string plate and bear upon a bridge 24 mounted upon the sounding board.

The string plate is secured directly to the back of the piano and is supported thereby through the medium of the uprights II'J and cross pieces I I by the anchor bolts 25.

The above is substantially the usual construction of the ordinary piano, but instead of the sounding board terminating along the lower edge of the pin block, it extends upwardly adjacent to the uppermost edge of the piano casing and is substantially spaced from the pin block by the spacing blocks 26 which are in turn well spaced from each other, as shown in Fig. 3. This provides for a free passageway 21 through which sound waves emanating from the sounding board I6 may pass upwardly and from the top of the piano.

Due to the fact that in the extreme treble it is desirable to stilTen the sounding board, a stiffening block may be provided between the sounding board and the back frame. as indicated at 28, the block 28 extending only a short way between the sounding board and back frame through the eX- treme treble portion and terminating before it reaches the middle or bass sections.

As indicated by the representation of the notes and the arrows, the sound waves emanating from the various bass, middle and treble sections of the sounding board may freely escape through the passageway 21 without the usual obstruction by the pin block heretofore present.

The invention claimed is:

l. In an upright piano structure, a back frame, a string plate carrying piano strings thereon, a pin block mounted adjacent the upper edge of the string plate, and a sounding board secured to the back frame and positioned between the back frame and string plate, said board extending from the bottom of the back frame to adjacent the top thereof and spaced from the pin block.

2. In an upright piano structure, a back frame, a string plate carrying piano strings thereon, a pin block mounted adjacent the upper edge of the string plate, and a sounding board secured to the back frame and positioned between the back frame and string plate, said board having the upper portion thereof spaced from the pin block and extending substantially coextensive therewith.

3. In an upright piano structure, a back frame, a string plate carrying piano strings thereon, a pin block mounted adjacent the upper edge of the string plate, a sounding board secured to the back frame and positioned between the back frame and string plate, the upper portion of said board being substantially coextensive with said pin block, and means for spacing the board from the pin block while providing an air passageway therebetween.

4. In an upright piano structure, a back frame, a string plate carrying piano strings thereon, a pin block mounted adjacent the upper edge of the string plate, and a sounding board secured to the back frame and positioned between the back frame and string plate with the upper portion of said board spaced from the pin block to permit free passage of sound waves therebetween and extending to adjacent the top of the back frame substantially coextensive with the pin block and the upper portion of the string plate.

5. In an upright piano structure, a back frame, a string plate carrying piano strings thereon, a pin block mounted adjacent the upper edge of the string plate, and a sounding board secured to the back frame and positioned between the back frame and string plate, said board extending from the bottom of the back frame to adjacent the top thereof with the upper portion thereof spaced from the pin block for permitting vibration independently thereof and the free passage of sound waves therebetween.

FRANCIS C. SOCIN. 

